Can this be clarified further? I've always been told that the exothermic combustion reaction releases energy in the form of light and heat, and that is what we see. But what of the flame itself? Is it physical, i.e. made up of matter, as dexter said? I tend to believe him, just looking at the structure it seems to have and the way it flickers and moves. But what physical matter that constitutes the flame is glowing? Ionised gas eh? From where? Thanks. It is just something I have always wondered about. The smoke is not puzzling...particulates from whatever the fuel source is (wood, etc). The flame, however, is.

Yes,it's a plasma,as i said and as any physics student learns in first lecture on plasma physics.A mixture of all possible microscopical objects.Heat is just KE of the components,while visible (and not) radiation comes from the continuous ionization & recombination of electrons,ions,atoms & molecules.